Such tractor trailer combinations generally comprise a trailer having a depressed flat loading platform and rear wheels, usually two or three tandem pairs; a tractor bearing the usual driving features and power sources and a fifth wheel; and a connection means known as a gooseneck connecting the tractor with the trailer. The connection means usually comprises an upstanding, generally vertical section adapted to be releasably secured to the front portion of the trailer and a generally horizontal beam secured to the top part of the upstanding section and extending forwardly to connect in articulated manner with the fifth wheel of the tractor. The upright section and generally horizontal beam connection means, because of the shape in side elevation, is commonly referred to as a gooseneck.
Since the tasks which such tractor-trailer rigs are called upon to perform are of a specialized, non-standard nature, it is of advantage to have a variety of different tractors, trailers and goosenecks available, all of which are interfitting with and detachable from one another. Accordingly, a tractor-trailer rig can be built according to the task it is to perform by selection of suitably sized components.
To load or unload heavy equipment such as a bulldozer from the trailer platform, it is necessary both to lower the trailer platform as close to the ground as possible, and to remove the gooseneck from the trailer. The power required for removal of the gooseneck from the trailer is normally derived from the tractor, or from self-contained power equipment on the gooseneck itself. In many instances the gooseneck has to be removed for loading or unloading cargo from the trailer in remote areas where other power sources and equipment are not conveniently available.